Several optical MEMS devices have been developed for minimally invasive diagnosis and therapy. Micro MEMS scanners have been developed for new endoscopes which enable high resolution inspection in the human body using a confocal microscopicsystem or optical coherence tomography. For realizing precis elaser treatment in the human body, a two-dimensional laser scanning micro tool has been also developed. Fiber-optic sensors have been developed for mechanical sensing, for example, local pressure or forces in the human body. Micro-mechanical sensing structures are fabricated using the MEMS process and installed at the tip of the optical fiber. This paper reviews optical MEMS devices developed for minimally invasive diagnosis and therapy.